Terrified I might have a brain tumor!?

You cannot jump to any kind of brain tumor diagnosis from these symptoms. It is more than likely your inner ear that is causing all of this. You can take an over the counter decongestant which may relieve some of your symptoms. You can also take some tylenol or motrin for the throbbing in your head which would be common sense. Follow the advice I have given, your symptoms may be completely gone by Tuesday but keep your appointment anyway so your doctor can re-evaluate the situation.